An Apparent Rôle for the Thymus (in Calcium Metabolism)

Abstract

IT has already been reported (Harris and Moore, Biochem. Jour., 23, 261; 1929) that hypervitaminosis D always involved an atrophy, indeed eventually virtual disappearance, of the thymus, and similar changes in other lymphadenoid tissue—a discovery which has since led us to the observation that an equally remarkable fall occurs in the lymphocyte count in the same circumstances, for example, down to a reduction of more than 90 per cent below the normal average range. The atrophy of the thymus might perhaps have been accounted for simply as a feature of the general inanition: a similar change is seen in vitamin B deficiency and sometimes in starvation: yet this explanation seemed unsatisfactory. Loss of weight, for example in vitamin A deficiency, does not always produce such an effect.